In a conventional binding line signatures to be included in a book are selected and gathered. In a binding line of one known form, a gathering section includes a gathering chain having a plurality of spaced pusher pins. One or more signature feeder stations are positioned above the gathering chain. The signature feeding stations are operated to feed a signature to the chain as it passes thereby. The timing of the signature feed coincides with each pusher pin approaching the feeder station. The signature comprises one or more sheets cut from a web and folded. The signatures straddle the chain at the fold line with the pusher pins bearing against a tail end of the signatures and forming the book as by a plurality of signatures being selectively deposited in sequence as the gathering chain moves beneath the feeding stations.
Once the signatures have been gathered, the book is transferred to a stitcher section. The stitcher section in one known form also includes a stitcher chain having a plurality of spaced pins for transporting signatures seriatim. Such a stitcher uses a two strand stitcher chain to allow stitcher clinchers to pass between the strands. The stitcher includes a flying stitcher head oscillating above the stitcher chain to drive staples through the gathered signatures at the fold line to secure the same.
In a binding line of the type described, the gathering chain and stitcher chain are synchronously operated. Both are driven in unison so that when a set of gathered signatures is delivered to an exit end of the gathering chain it can be suitably picked up at an entry end of the stitcher chain. An overhead transfer station transfers signatures from the gathering chain to the stitcher chain. The transfer station includes a fixed saddle plate extending between the gathering section exit end and the stitcher section entry end and an endless overhead chain having a plurality of spaced pusher pins. The overhead chain is also driven synchronously with the gathering chain and stitcher chain to provide continuous uninterrupted operation.
In design of a binding line, various parameters must be considered. These parameters include the ability to assemble books of different sizes and the ability to assemble the books without damaging the books.
A binding line as previously described usually includes pin spacing on the order of twenty-one inches on both the gathering chain and stitcher chain. Both the gathering chain and stitcher chain are driven by a common drive system. Indeed, a main drive shaft is used for driving all related equipment to provide synchronization, including operation of the signature feeders and the stitcher. With any given system the main drive will operate to provide a select cycle time. As is apparent, with twenty-one inch spacing the chain moves at twenty-one inches per cycle. With shorter pin spacing, for example fifteen inch pin spacing, the chain moves at a rate of fifteen inches per cycle. One advantage to using twenty-one inch spacing is that it allows for the line to be used with virtually any sized book. However, the higher rate of speed can damage the signatures as the pusher pins are moving at a higher rate of speed when they impact the tail end of the book as the signatures are gathered. The closer spacing, on the order of fifteen inches, provides a slower operating speed to lessen damage. However, such a system cannot handle all size books.
In view of the above, it is apparent that a need exists to obtain the benefits of longer and shorter pin spacing, i.e., have the ability to operate a relatively long pin spacing, on the order of twenty-one inches, while using a shorter pin spacing, on the order of fifteen inches, when possible to improve efficiency on a single binding line. Heretofore, all known binding lines of the type discussed above have operated both the gathering chain and stitcher chain to have the same pin spacing and operate at the same velocity.
The present invention is directed to solving one or more of the problems discussed above in a novel and simple manner.